- What is Diabetes Insipidus – Central
- Statistics on Diabetes Insipidus – Central
- Risk Factors for Diabetes Insipidus – Central
- Progression of Diabetes Insipidus – Central
- Symptoms of Diabetes Insipidus – Central
- Clinical Examination of Diabetes Insipidus – Central
- How is Diabetes Insipidus – Central Diagnosed?
- Prognosis of Diabetes Insipidus – Central
- How is Diabetes Insipidus – Central Treated?
- Diabetes Insipidus – Central References
What is Diabetes Insipidus – Central
Diabetes Insipidus – central occurs as a result of a disorder in the hypothalamus or pituitary gland in the brain.
Diabetes insipidus (DI) is an uncommon condition that occurs when the kidneys are unable to conserve water as they perform their function of filtering blood. The amount of water conserved is controlled by antidiuretic hormone (ADH, also called vasopressin).
ADH is a hormone produced in a region of the brain called the hypothalamus. It is then stored and released from the pituitary gland, a small gland at the base of the brain.
DI caused by a lack of ADH is called central diabetes insipidus. When DI is caused by failure of the kidneys to respond to ADH, the condition is called nephrogenic diabetes insipidus. The major symptoms of diabetes insipidus are excessive urination and extreme thirst. The sensation of thirst stimulates patients to drink large amounts of water to compensate for water lost in the urine.
Statistics on Diabetes Insipidus – Central
DI is uncommon, with a prevalence of 1 case per 25,000 people.
No significant sex differences in central or nephrogenic DI exist. Male and female prevalence are equal. Although rare, central DI is more common than nephrogenic DI.
Risk Factors for Diabetes Insipidus – Central
Central diabetes insipidus is caused by damage to the hypothalamus or pituitary gland as a result of surgery, infection, tumor, or head injury. Recent literature indicates 30% of cases to be idiopathic, 25% related to malignant or benign tumors of the brain or pituitary, 16% secondary to head trauma, and 20% following cranial surgery.
Progression of Diabetes Insipidus – Central
If thirst mechanisms are normal and adequate fluids are consumed, there are no significant effects on body fluid or salt balance. If inadequate fluids are consumed, the large amount of water lost in the urine may cause dehydration and high sodium levels in the blood. This can cause potentially fatal dehydration with shock and hypernatraemia.
How is Diabetes Insipidus – Central Diagnosed?
- Urinalysis – specific gravity;
- Serum electrolytes and osmolality – especially hypernatraemia;
- MRI of the head, revealing an abnormality in or near the pituitary gland.
Prognosis of Diabetes Insipidus – Central
How is Diabetes Insipidus – Central Treated?
The cause of the underlying condition should be treated.
Vasopressin (desmopressin) will be administered either as a nasal spray, oral tablets, or injections under the skin. This controls the urine output and fluid balance, and prevents dehydration.
In mild cases, increased water intake may be all that is needed. If the thirst mechanism is not working (for example, if a part of the brain called the hypothalamus is damaged), a presciption for a certain amount of water intake may also be needed (usually 2-2.5 L per day) to ensure proper hydration.
Diabetes Insipidus – Central References
- Cooperman, M. Diabetes Insipidus, 2003 Temple University.
- Diabetes insipidus – central as retrieved from www.nlm.nih.gov
- Kumar, P., Clark, M. Clinical Medicine 5th Ed. 2002 WB Saunders.